Method and apparatus for simultaneously mortising butt seats in a door and its jamb

ABSTRACT

Matching seats for hinge leaves are cut simultaneously in a door and its jamb while the door is fixed temporarily in the jamb in service position. A series of overlapping cylindrical bores centered on the longitudinal median of the clearance crack between the door and jamb is plunge cut simultaneously half in the door and half in the jamb by a single rotary cutting tool which then is traversed longitudinally along the series to remove the material remaining between the overlaps, thereby providing parallel straight sidewalls constituting a mortise in the door and jamb complemental to a hinge by which the door is to be hung.

United States Patent Oct. 12, 1971 METHOD AND APPARATUS FOR SIMULTANEOUSLY MORTISING BUTT SEATS IN A DOOR AND ITS JAMB 3 Claims, 7 Drawing Figs.

US. Cl 144/27, 144/70, 144/325 Int. Cl B271 5/12 Field of Search 144/27, 70,

Primary Examiner-Donald R. Schran Attorney-Townshend & Meserole ABSTRACT: Matching seats for hinge leaves are cut simultaneously in a door and its jamb while the door is fixed temporarily in the jamb in service position. A series of overlapping cylindrical bores centered on the longitudinal median of the clearance crack between the door and jamb is plunge cut simultaneously half in the door and half in the jamb by a single rotary cutting tool which then is traversed longitudinally along the series to remove the material remaining between the overlaps, thereby providing parallel straight sidewalls constituting a mortise in the door and jamb complemental to a hinge by which the door is to be hung.

PATENTED w 1 2 I971 3 s 1 2,1 18

SHEET 1 OF 3 FIG. I

INVENT OR RUSSELL K. DAVIS lav M; Zf-4-6 ATTORNEY 5'.

PATENTED um 1 219m SHEET 2 [1F 3 FIG. 7

RUSSELL Kl DAVIS FIG 2 ATTORNEYS.

PA TENTEDIJCHIZIHYI 3512.118

ATTORNEYS,

BY/Mm/ BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is primarily concerned with a method for simultaneously cutting, in a door and its jamb, perfectly matching seats for the leaves of a hinge by which the door is to be hung in the jamb. Secondarily, the invention relates to apparatus by which the method may be practiced.

2. Description of the Prior Art The prior art teaches the broad idea of mortising matching hinge-leaf seats simultaneously in a door and the jamb in which it is to be hung; the most pertinent examples of which are US. Pat. Nos. 3,038,509; 3,068,917 and 1,012,241. These require the use of specially designed tools that ordinarily are not readily available to a journeyman carpenter.

SUMMARY OF THE INVENTION The present invention provides a novel, inexpensive, simple method and apparatus which involves nothing more than operating a rotary plunge-cutting tool to cut a series of mating, half-cylindrical bores simultaneously in a door and its jamb, and removing the material left between the bores simply by traversing the same cutting tool along the series from end to end thereof. The bores cut by the tool are parallel, overlapping, and are centered axially on the longitudinal median of the crack between the door and its jamb.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation of a door temporarily mounted in service position in a jamb inwhich it is to be hung, and equipped with a pair of butt jigs for carrying out the method of this invention.

FIG. 2 is an enlarged fragmentary elevation of one of the two identical butt jigs shown in FIG. I, at completion of the mortise cut.

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2.

FIG. 4 is a fragmentary elevation similar to FIG. 1, but illustrating the series of mortise half-bores as plunge out prior to completion of the mortise by traversing the cutting tool.

FIG. 5 is a sectional view taken on line 5-5 of FIG. 3.

FIG. 6 is a sectional view taken on line 6-6 of FIG. 3.

FIG. 7 is a sectional view taken on line 77 of FIG. 5.

DESCRIPTION OF PREFERRED EMBODIMENT It is appropriate at this point to repeat and to emphasize the fact that the invention with which this application is chiefly concerned is the method, later described, and that the following detailed description of apparatus relates to the best means I have thus far devised for reducing the method to practice.

As here shown, the apparatus is a butt jig in which a cutting tool bushing 9 mounted in the bushing carrier 10 of a rotarycutting tool is detachably carried by, and is movable to various positions longitudinally along, a flat indexing bar 11 which is supported at each of its ends by a locator unit designated generally by reference character 12. Each locator unit, in the form here shown, comprises a pair of laterally spaced, parallel sidearms 13 integrally connected at one end by a flat connector strip 14 disposed in a plane normal to the planes of the sidearms 13. The connector strip 14 is extended laterally beyond the adjacent ends of the arms 13 to provide a flat finger 15 which extends inwardly in the crack between the door and its jamb when the jig is applied in service position. Heavily burred holes 16 punched through the finger enhance the frictional engagement between the finger and the surfaces of the door and the jamb. The opposite (outer) ends of the sidearms 13 each are formed with an open outer end slot 17 closed at its inner end. The closed end walls of the slots 17 provide seats against which the adjacent end portion of the indexing bar 11 abuts when it is slid inwardly in the slots into its service position as shown in FIGS. 2 and 6. That part of the end portion of the bar 11 which extends between the sidearms 13 of the upper locator 12 is apertured to receive therethrough a bolt shank 18 having at its outer end a head 19 for bearing against a washer 20 interposed between the bolthead and the outer face of the bar 11. The inner end of the bolt shank extends through a complemental aperture in the strip 14 and projects therebeyond as a threaded end portion mounting a wingnut 21 by which the indexing bar 11 may be clamped securely against the inner end wall seats of the slots 17, as shown in FIG. 6, in fixed relation.

That part of the lower end of indexing bar 11 which extends between the sidearms 13 of the lower locator 12 is provided with a longitudinal closed end slot 11 to accommodate its associated bolt shank 18. As seen in FIG. 2, the bolthead 19 of the lower locator 12 is backed by a washer similar to the washer 20 of the upper locator but having an integral extension 20' that provides a stop against which the plate 30 of the bushing carrier frame abuts to define the lower limit position which the bushing carrier 10 may reach along the indexing bar 11. The distance between the lower arm 13 of the upper locator 12 (which constitutes a stop defining the upper limit position of the bushing carrier) and the stop 20' of the lower locator determines the length of the mortise cut. If it be desired to lengthen the out beyond its extent as seen in FIG. 3, the lower wingnut 21 is loosened to permit the stop 20' to be moved downward along the indexing bar 11 for the required distance. Stop 20' is adjustable longitudinally on bar 11.

The bushing carrier 10 is fixed in a wide U-shaped support frame having parallel sidewalls 22 connected to one end by a bight portion 23 that is arranged in slidable face contact with the indexing bar 11. The cutting tool arbor 24 passes through and projects externally beyond the frame walls 22. At its inner end the arbor mounts a rotary plunge-cutting tool 25 which, when the jig is in service position, has its axis of rotation centered on the longitudinal median of the normal clearance crack between the door and its jamb. The outer end portion of arbor 24 seats in a socket 26 at one end portion of a stop arm 27 that (with respect to FIG. 3) serves to limit the axial extent to which the tool 25 may be pulled out from the mortise recesses during indexing. Stop arm 27 is pivoted at its other end portion on a stud bolt 28 passed through the arm and through a lateral flange extension 29 on the outer end of a plate 30 which at its inner end has fixed attachment to the bight portion 23 connecting the sidewalls 22 of the bushing carrier frame. A wingnut 31 threaded on the outer end of stud bolt 28 serves to clamp stop arm 27 in a set position.

The jig is equipped with means for indexing the bushing carrier assembly longitudinally along the bar 11 into successive mortise-cutting positions. For this purpose the bar is provided with a longitudinal series of through holes 32 in closely spaced relationship over the major length of the bar. These holes 32 are sockets for selective reception of a detent, here shown as a pin 33 on the inner end of a plunger 34, that is biased to projected position by an expansion spring 35 to hold the pin seated in a selected one of the holes 32, as shown in FIG. 7, and thereby lock the carrier assembly against movement longitudinally along the bar 11. Plunger 34 and its surrounding spring 35 are housed within a cylindrical casing 36 that is open at its outer end and crenelated to provide an annular series of diametrically opposed slot sockets 37 and 38 that seat the cross-rod handle 39 which is fixedly attached to the outer end of the plunger 34. The opposed slots 37 are of the same depth, which depth is greater than the depth of the opposed slots 38. By this arrangement, as seen in FIG. 7, when handle rod 39 is fully seated in a pair of the diametrically opposed slots 37, the pin 33 is fully engaged in a selected one of the indexing bar holes 32; and when the handle rod is fully engaged in a pair of the shallower slots 38, the pin 33 is fully disconnected from the bar 11 so that the bushing carrier assembly may be shifted longitudinally along the bar. The inner end of casing 36 has a laterally enlarged head 40 which together with the adjacent end portion of the plate 30, is riveted to the bight portion 23 of the motor frame.

The rotary-cutting tool 25 is so designed that it will cut a cylindrical bore during axial-advancing movement, and during lateral-advancing movement it will cut out a slot corresponding in depth and width to the length and diameter, respectively, of the cutter. The width of the mortise slot is determined by the setting of a stop collar 41 that is adjustable axially on the arbor shaft 24 to limit the axial extent to which the tool 25 may be moved into the crack between the door and its jamb.

METHOD OF OPERATION In the practice of my invention, a door 42 that is to be hung in a jamb 43 is temporarily positioned in the jamb frame so that it is in service position as shown in FIG. I. A butt jig in which the stop 20' and the shaft collar 41 are set to define the length and depth of the mortise slot is placed at the desired location for the lower door hinge installation. The fingers 15 at the upper and lower ends of the jig are inserted in the crack between the jamb and the door on its hinge side, and spacers 44 are driven between the bottom edge of the door and the floor to provide proper swing clearance at the top and the bottom of the door. Wedges 45 are driven into the crack between the jamb and the knob side of the door. The spacers 44 and wedges 45 hold the door firmly in service position until completion of the mortise cuts. A second butt jig, with its stop 20 and shaft collar 41 set to define the length and depth of mortise slot, is placed at the desired location for the upper door hinge installation, and its locator fingers 15 are forced into the crack between the jamb and the door.

The locator fingers 15 of both jigs are forced into the clearance crack until the inner ends of the sidewalls 13 of the locators l2 abut the adjacent outer face of the door, against which they are firmly seated.

The bushing carrier assembly mounting is then placed in abutting engagement with either one locator 12 or the traverse stop 20' of its associated locator at that end of the jig where the mortise cut is to being, and the spring-pressed locking pin 33 (see FIG. 7) is seated in the nearest available one of the socket holes 32 of the indexing bar 1 l. The bushing carrier 10 with its attached cutting tool 25 is then inserted through complemental apertures in the sidewalls 22 of the frame 23. In this position the axis of the rotary cutting tool 25 will be exactly centered on the longitudinal median of the crack between the door and the jamb, with the bit of the cutter bearing equally on both; so that as the rotating cutter is advanced inwardly into the crack it will out half in the door and half in the jamb. The diameter of the cutting tool 25 determines the depth of the mortise slot.

By successive disengagements and reengagements of the locking pin 33, and corresponding disengagements and reengagements of the cutting tool, the drill may be indexed longitudinally along the bar 11 until the bushing carrier frame assembly abuts either the stop 20 or the locator I2 at the other end of the mortise. This results in the creation of a series of overlapping, semicylindrical bores 46 in the opposed side edge faces of the door jamb, as seen in FIG. 4.

After the last of the bores 46 is cut, and without removing the cutter 25 therefrom the locking pin 33 is pulled out of its socket hole in the bar I I; so that the entire rotary cutter unit is free for movement longitudinally along the bar 11 in opposite directions. The operating handle 39 of the locking pin then is seated in the pair of slots 38 and thus the pin is held disengaged from the bar 11 so long as the handle 39 remains seated in the slots 38. The unit comprising the bushing carrier assembly and rotary cutter, with the cutter in operation, is then traversed back and forth from end to end of the longitudinal series of the bores 46. The rake of the cutter 25 is such that during its traverse movement its cutting edge effectively cuts away all the body material of the door and the jamb remaining between the bores overlaps, resulting in a fiat, planar face 47 for the inner wall of each mortise 48 in place of the unfinished serrated wall constituted by the initial bores 46 shown in FIG.

4. Accordingly, each mortise recess is of the proper depth and length to seat a leaf of a hinge (not shown) so that the outer face of the leaf will be flush with the side edge face of the door or jamb in which it seats. After finishing the mortises 48 by traverse of the cutter as above described, the jigs are removed together with the spacers 44 and wedges 45 and the door is dismounted. It is a simple matter then to seat a hinge leaf in each of the mortises 48 and secure it by conventional means.

The rotary-cutting tool 25 is operated by rotation of the reduced shaft portion of the arbor 24. As here shown in FIG. 5, the arbor is driven by a portable motor 50, such as a conventional electrical drill motor or air motor, detachably coupled to the outer end of the arbor shaft. The motor is not a part of the jig itself, but is applied only when the cutting tool is to be put in operation.

lclaim:

l. The method of simultaneously mortising the opposed side edge faces of a door and its jamb, which comprises: positioning a portion of a door and its jamb in adjacent relation; operating a rotating cutting tool to plunge cut a series of parallel, overlapping cylindrical bores simultaneously half in the door side edge face and half in the jamb side edge face; and traversing the same rotating cutter tool from end to end of the completed series of bores by moving the rotating cutter through the bore area laterally relative to its axis of rotation, thereby cutting away all the door and jamb material between the overlapped bores to provide a smooth parallel-walled opening.

2. The method of butt-mortising a door and its jamb, which comprises: anchoring the door and its jamb temporarily in door-closed relationship; plunge cutting a series of laterally overlapping substantially semicylindrical bores simultaneously in the opposed side edge faces of the door and the jamb by a rotating cutting tool indexed longitudinally along the crack between the faces with its axis of rotation centered in the longitudinal median of the crack; and traversing the rotating cutting tool laterally relative to its axis of rotation from one end of the series of bores to its other end and thereby cutting away all the material of the door and the jamb remaining between the overlapped bores at the conclusion of their formation.

3. A butt-mortise-cutting jig comprising, in combination: a rotary-cutting tool; means for operating the tool in the crack between a door and its jamb on an axis of rotation at a right angle to the door face and centered on the longitudinal median of the crack; means operative to limit selectively advance of the cutting tool axially into the crack, whereby to predetermine the width of a mortise to be cut by operation of the tool; indexing means operative to index the cutting tool and its operating means longitudinally along the crack whereby to cut simultaneously half in the door and half in the jamb a series of parallel, overlapping cylindrical bores; and stop means operative by engagement with a part of the cutting-tool-operating means to define opposite end limits of indexing travel of the tool and thereby determine the length of the series of bores to be cut to form a mortise; said indexing means including a bar; the rotary-cutting-tool-operating means being slidable on said bar for movement longitudinally thereon between said stop means; a support for the bar at each end thereof; and each said support having a locator finger for insertion in the crack between the door and the jamb. 

1. The method of simultaneously mortising the opposed side edge faces of a door and its jamb, which comprises: positioning a portion of a door and its jamb in adjacent relation; operating a rotating cutting tool to plunge cut a series of parallel, overlapping cylindrical bores simultaneously half in the door side edge face and half in the jamb side edge face; and traversing the same rotating cutter tool from end to end of the completed series of bores by moving the rotating cutter through the bore area laterally relative to its axis of rotation, thereby cutting away all the door and jamb material between the overlapped bores to provide a smooth parallel-walled opening.
 2. The method of butt-mortising a door and its jamb, which comprises: anchoring the door and its jamb temporarily in door-closed relationship; plunge cutting a series of laterally overlapping substantially semicylindrical bores simultaneously in the opposed side edge faces of the door and the jamb by a rotating cutting tool indexed longitudinally along the crack between the faces with its axis of rotation centered in the longitudinal median of the crack; and traversing the rotating cutting tool laterally relative to its axis of rotation from one end of the series of bores to its other end and thereby cutting away all the material of the door and the jamb remaining between the overlapped bores at the conclusion of their formation.
 3. A butt-mortise-cutting jig comprisinG, in combination: a rotary-cutting tool; means for operating the tool in the crack between a door and its jamb on an axis of rotation at a right angle to the door face and centered on the longitudinal median of the crack; means operative to limit selectively advance of the cutting tool axially into the crack, whereby to predetermine the width of a mortise to be cut by operation of the tool; indexing means operative to index the cutting tool and its operating means longitudinally along the crack whereby to cut simultaneously half in the door and half in the jamb a series of parallel, overlapping cylindrical bores; and stop means operative by engagement with a part of the cutting-tool-operating means to define opposite end limits of indexing travel of the tool and thereby determine the length of the series of bores to be cut to form a mortise; said indexing means including a bar; the rotary-cutting-tool-operating means being slidable on said bar for movement longitudinally thereon between said stop means; a support for the bar at each end thereof; and each said support having a locator finger for insertion in the crack between the door and the jamb. 